/**
 * @file md5.cpp
 * @brief MD5 implementation
 * @author Zhang peihao
 */

#include <zsystem/core/common/md5.h>
#include <memory.h>
#include <string>

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
  ( w += f(x, y, z) + data, w &= 0xffffffff, w = w<<s | w>>(32-s), w += x )

static Z_U32 getu32 (const Z_U8 *addr)
{
  return (((((Z_U32)addr[3] << 8) | addr[2]) << 8)
          | addr[1]) << 8 | addr[0];
}

static void putu32 (Z_U32 data, Z_U8 *addr)
{
  addr[0] = (Z_U8)data;
  addr[1] = (Z_U8)(data >> 8);
  addr[2] = (Z_U8)(data >> 16);
  addr[3] = (Z_U8)(data >> 24);
}

static void md5Transform (Z_U32 buf[4], const Z_U8 inraw[64])
{
  register Z_U32 a, b, c, d;
  Z_U32 in[16];
  int i;

  for (i = 0; i < 16; ++i)
    in[i] = getu32 (inraw + 4 * i);

  a = buf[0];
  b = buf[1];
  c = buf[2];
  d = buf[3];

  MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478,  7);
  MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
  MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
  MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
  MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf,  7);
  MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
  MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
  MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
  MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8,  7);
  MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
  MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
  MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
  MD5STEP(F1, a, b, c, d, in[12]+0x6b901122,  7);
  MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
  MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
  MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);

  MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562,  5);
  MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340,  9);
  MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
  MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
  MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d,  5);
  MD5STEP(F2, d, a, b, c, in[10]+0x02441453,  9);
  MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
  MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
  MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6,  5);
  MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6,  9);
  MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
  MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
  MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905,  5);
  MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8,  9);
  MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
  MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);

  MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942,  4);
  MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
  MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
  MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
  MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44,  4);
  MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
  MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
  MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
  MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6,  4);
  MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
  MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
  MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
  MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039,  4);
  MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
  MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
  MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);

  MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244,  6);
  MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
  MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
  MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
  MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3,  6);
  MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
  MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
  MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
  MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f,  6);
  MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
  MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
  MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
  MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82,  6);
  MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
  MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
  MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);

  buf[0] += a;
  buf[1] += b;
  buf[2] += c;
  buf[3] += d;
}


void zsystem::md5::reset()
{
  _data.buf[0] = 0x67452301;
  _data.buf[1] = 0xefcdab89;
  _data.buf[2] = 0x98badcfe;
  _data.buf[3] = 0x10325476;

  _data.bits[0] = 0;
  _data.bits[1] = 0;
}

void zsystem::md5::update(Z_U8 const *buf, Z_U32 len)
{
  Z_U32 t;

  /* Update bitcount */
  t = _data.bits[0];
  if ((_data.bits[0] = (t + ((Z_U32)len << 3)) & 0xffffffff) < t)
    _data.bits[1]++;  /* Carry from low to high */
  _data.bits[1] += len >> 29;

  t = (t >> 3) & 0x3f;  /* Bytes already in shsInfo->data */

  /* Handle any leading odd-sized chunks */

  if(t)
  {
    Z_U8 *p = _data.in + t;

    t = 64-t;
    if(len < t)
    {
      memcpy(p, buf, len);
      return;
    }
    memcpy(p, buf, t);
    md5Transform(_data.buf, _data.in);
    buf += t;
    len -= t;
  }

  /* Process data in 64-byte chunks */
  while (len >= 64)
  {
    memcpy(_data.in, buf, 64);
    md5Transform (_data.buf, _data.in);
    buf += 64;
    len -= 64;
  }

  memcpy(_data.in, buf, len);  
}
void zsystem::md5::getResult(Z_U8 result[16])
{
  Z_U32 count;
  Z_U8 *p;

  /* Compute number of bytes mod 64 */
  count = (_data.bits[0] >> 3) & 0x3F;

  /* Set the first char of padding to 0x80.  This is safe since there is
    always at least one byte free */
  p = _data.in + count;
  *p++ = 0x80;

  /* Bytes of padding needed to make 64 bytes */
  count = 64 - 1 - count;

  /* Pad out to 56 mod 64 */
  if(count < 8)
  {
    /* Two lots of padding:  Pad the first block to 64 bytes */
    memset(p, 0, count);
    md5Transform (_data.buf, _data.in);

    /* Now fill the next block with 56 bytes */
    memset(_data.in, 0, 56);
  }
  else
  {
    /* Pad block to 56 bytes */
    memset(p, 0, count-8);
  }

  /* Append length in bits and transform */
  putu32(_data.bits[0], _data.in + 56);
  putu32(_data.bits[1], _data.in + 60);

  md5Transform (_data.buf, _data.in);
  putu32(_data.buf[0], result);
  putu32(_data.buf[1], result + 4);
  putu32(_data.buf[2], result + 8);
  putu32(_data.buf[3], result + 12);
}

void zsystem::md5::getResultString(char result[33])
{
  Z_U8 byteRes[16];
  getResult(byteRes);
  for(int i = 0; i < 16; ++i)
    Z_SNPRINTF(&result[i*2], 3, "%02x", (unsigned int)byteRes[i]);
  result[32] = '\0';
}





